1. Field
The present disclosure relates to an oil level gauge mounting structure.
2. Description of the Related Art
In order to check the amount of oil held in the oil pan of an automotive internal combustion engine, a stick-shaped or belt-shaped oil level gauge is provided according to the related art. Furthermore, there is a related technology in which an oil return passageway is used as a passageway for an oil level gauge in order to, for example, make a compact engine (see, e.g., Japanese Unexamined Patent Application Publication No. 2006-189001). Since the oil return passageway is not provided as an passageway for the oil level gauge, a gauge surface provided on a distal end portion of the oil level gauge is provided with a guard wall portion extending over the entire length of the gauge surface and protruded from the gauge surface in a direction orthogonal to the gauge surface so that when the oil level gauge is inserted into or pulled out of the oil return passageway, the gauge surface does not contact a wall surface of the oil return passageway.
Not only in the case where an oil return passageway as mentioned above is utilized as a passageway for an oil level gauge but also in the case where a passageway dedicated to an oil level gauge is provided, if the oil level gauge passageway is curved due to constrictions for a compact design of the internal combustion engine or if the engine is mounted in an inclined posture, there is a need to direct the gauge surface in such a predetermined direction as to reduce the contact between the gauge surface and the wall surface of the passageway.
As for the oil level gauge of Japanese Unexamined Patent Application Publication No. 2006-189001, in order to ensure that the oil level gauge will be mounted so that the gauge surface will face such a predetermined direction as to avoid contacting a bolt used to attach an oil-circulating pump, there is provided such an arrangement that the mounting of the oil level gauge cannot be completed unless the gauge surface is directed in the predetermined direction by engaging a cutout portion provided in a collar portion provided in an upper portion of the oil level gauge with a V-shaped projection portion provided on a head cover.
On another hand, in an assembly process at a factory, standardization of operations is required, so that there is a need to provide a measure to restrict the direction in which an operating person's finger is inserted in the grip portion. For example, there exists a related-art technology in which the head cover is provided with a recess portion that has three wall surfaces that surround the grip portion (knob portion) on three sides (see Japanese Registered Utility Model No. 2587583). According to this technology, when the mounting of an oil level gauge is performed, an operating person's finger is inserted in the grip portion (knob portion) so that a distal end portion of the finger reaches a deeper side in the recess portion. Thus, the finger insertion direction relative to the grip portion (knob portion) can be restricted.